Copy unmanaged DLL from NuGet package to ASP.NET API

My problem is that I have an unmanaged library in a nuget package that I want to copy in the publish folder of the API that embed it.

Here is a StackoverFlow post that I thought it could work as the final goal seems to be the same as me : Include Unmanaged DLL from Nuget package to web Deploy package And here is how I tried to adapt it to my project :

<Target Name="AfterBuild" DependsOnTargets="CopyFilesToOutputDirectory">
    <ItemGroup>
      <MyPackageSourceFile Include="$(SolutionDir)Assemblies\libwkhtmltox\64 bits\libwkhtmltox.dll" />
    </ItemGroup>
    <Copy SourceFiles="@(MyPackageSourceFile)" DestinationFolder="$(OutputPath)" />
    <Copy SourceFiles="@(MyPackageSourceFile)" DestinationFolder="$(ProjectDir)UnmanagedDll" />
  </Target>

  <Target Name="AddUnmanagedDll" AfterTargets="AfterBuild">
    <ItemGroup>
      <Content Include="UnmanagedDll\*.dll" />
    </ItemGroup>
  </Target>

But it doesn't do anything .

In a more common way I also tried something kind of this :

<ItemGroup>
    <None Remove="Assemblies\libwkhtmltox\32 bits\libwkhtmltox.dll" />
    <None Remove="Assemblies\libwkhtmltox\64 bits\libwkhtmltox.dll" />
  </ItemGroup>
<ItemGroup>
    <ContentWithTargetPath Include="Assemblies\libwkhtmltox\32 bits\libwkhtmltox.dll">
      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
      <TargetPath>Assemblies\libwkhtmltox\32 bits\libwkhtmltox.dll</TargetPath>
    </ContentWithTargetPath>

    <ContentWithTargetPath Include="Assemblies\libwkhtmltox\64 bits\libwkhtmltox.dll">
      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
      <TargetPath>Assemblies\libwkhtmltox\64 bits\libwkhtmltox.dll</TargetPath>
    </ContentWithTargetPath>
  </ItemGroup>

Maybe it could be important to specify that all the projects are in C# .NET CORE 2.1

Please tell me if you want any further information.